The present invention relates to a workpiece supplying apparatus and a workpiece supplying method.
Japanese Laid-Open Patent Publication No. 2010-143685 describes a workpiece supplying apparatus including a plurality of carriers and a carrier case, which accommodates the carriers. Each carrier holds a plurality of workpieces such that the workpieces are arranged in a one-dimensional manner. Each carrier is drawn out from the carrier case by an unloading device at arranged intervals of the workpieces held by that carrier. The workpieces held by the carrier are sequentially unloaded from the carrier at a predetermined unloading position and arranged at a processing position on a workbench. The carrier from which the workpieces are unloaded is guided by roller-shaped inner guides. A transporting direction of the carrier is reversed by 180° as the carrier moves downward, and the carrier is accommodated in a collecting case. In such a workpiece supplying apparatus, workpieces are unloaded only at the unloading position. This allows for such equipment to be relatively compact.
However, the carrier of Japanese Laid-Open Patent Publication No. 2010-143685 has a front surface including a plurality of pockets that are arranged in a single row. Each pocket is shaped in correspondence with the outer shape of the workpieces. The pockets are recessed from the front surface of the carrier. The workpieces are accommodated and held in the pockets. This structure holds the workpieces in a preferable manner. However, the carrier has a rear surface including projections, which are formed in correspondence to the pockets. Thus, when the carrier is reversed, the pockets interfere with each other or with the inner guides. This hinders smooth transportation of the carrier.
Further, in such a workpiece supplying apparatus, it is necessary to arrange the carrier case, which accommodates the workpieces, at a position (unloading position) where the unloading device can unload the carriers. Thus, a tray changer may be arranged in the vicinity of the workbench. The A plurality of carrier cases accommodating workpieces is stacked onto the tray changer. The tray changer moves one of the carrier cases to the unloading position. Then, when unloading of the workpieces from the carrier case is completed, the tray changer moves an empty carrier case, which has no workpieces from the unloading position, and moves the next carrier case accommodating workpieces to the unloading position.
However, when there is a workbench for each processing operation, a tray changer, which is large, must be provided for every workbench. The workbench and the tray changer required for each processing operation increases the area occupied by the equipment.
Further, in the above publication, the carrier includes accommodation recesses (workpiece-receiving pockets), which receive workpieces. To prevent the workpiece from falling out of the accommodation recess of the carrier, a structure such as a cover tape has to be thermally welded to the front surface of the carrier to close the accommodation recesses. However, thermal welding of the cover tape would make it difficult to reuse the carrier and thereby raise costs.